Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Polar ice may be softer than we thought

22.06.2018

Tübingen and international researchers investigate ice flow speed in northern Greenland, correcting models predicting sea level change

Ice is a material that can flow like a very viscous liquid. In the polar ice sheets, it flows towards the oceans under its own weight. Knowing how fast the ice flows is of crucial importance to predict future sea level rises, particularly under changing climate conditions.

Professors Paul Bons and Ilka Weikusat from the University of Tübingen’s Geosciences Department, working with scientists from the Alfred Wegener Institute in Bremerhaven, the University of Otago (New Zealand) and the Autonomous University of Barcelona (Spain), measured flow velocities at the surface of the northern Greenland Ice Sheet for a new study now published in Geophysical Research Letters. Their analysis of satellite images suggests that the polar ice is softer than scientists believed until now.

The flow has two components: the internal shearing flow that depends on the viscosity of the ice, and basal motion, which is the ice sheet sliding along the bedrock, especially when the ice melts at that base. The satellite images revealed the surface velocities of the ice, which the researchers used to calculate the stresses that drive the flow.

Previous studies indicated that up to 50 percent of the Greenland Ice Sheet is melting at its base. “This new study shows that that is probably overestimated, because previous studies assumed ice to be harder than it actually is,” says Paul Bons. The new assessment significantly reduces the area where basal motion – and therefore basal melting can be expected in the Greenland study area.

“This does not necessarily mean that ice will now enter the oceans more slowly and delay sea-level rise. Instead, the results suggest that the internal deformation of ice is more important than was thought before,” Ilka Weikusat explains. The new findings will be used to adapt the models predicting sea level changes.

The share of ice transport towards the oceans between melting at the base or internal shearing of the whole ice body has to be reconsidered, but cannot be determined from surface data alone. Instead, deep drill cores into fast flowing ice are important, such as the ongoing EastGRIP project in which some of the authors are involved.

Publication:
Bons, P.D., Kleiner, T., Llorens, M.G., Prior, D.J., Sachau, T., Weikusat, I. Jansen, D.
Greenland Ice Sheet – Higher non linearity of ice flow significantly reduces estimated basal motion. Geophysical Research Letters. First published: 19 June 2018. Doi:10.1029/2018GL078356
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078356

Contact:
Professor Dr. Paul D. Bons
University of Tübingen – Faculty of Science
Geosciences – Structural Geology
Phone +49 7071 29-76469
paul.bons[at]uni-tuebingen.de

Junior Professor Dr. Ilka Weikusat
University of Tübingen – Faculty of Science – Geosciences – Glaciology
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
Phone +49 471 4831 1968
ilka.weikusat[at]uni-tuebingen.de

Dr. Karl Guido Rijkhoek | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-tuebingen.de/

More articles from Earth Sciences:

nachricht Glacial engineering could limit sea-level rise, if we get our emissions under control
20.09.2018 | European Geosciences Union

nachricht Warning against hubris in CO2 removal
20.09.2018 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

 
Latest News

Glacial engineering could limit sea-level rise, if we get our emissions under control

20.09.2018 | Earth Sciences

Warning against hubris in CO2 removal

20.09.2018 | Earth Sciences

Halfway mark for NOEMA, the super-telescope under construction

20.09.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>